1. Field of the Invention
The present invention relates to a video processing apparatus for executing, when an input video signal is displayed on a display apparatus, a video processing for magnifying a video signal to an arbitrary size, and a control method for the video processing apparatus.
2. Description of the Related Art
In recent years, after the launch of digital broadcasting, popularization of a high image quality video such as HD (High Definition) having 1920×1080 pixels has been advanced. Furthermore, videos with a higher image quality than the HD are being proposed such as a digital cinema having about four times as many as the number of pixels of the HD (4096×2160) and UHD (Ultra High Definition) having about 16 times as many as the number of pixels of the HD (7680×4320). In accordance with the situation, trends of a larger screen and a higher definition are also progressed in display apparatuses including a display and a projector for displaying these videos.
In a case where a video having the small number of pixels such as a SD (Standard Definition video is displayed on a display apparatus having the large screen and high definition, when one pixel of the SD video is allocated to one pixel of the display apparatus having the large number of pixels, the display size becomes smaller as compared with the screen size, and visibility is not satisfactory. For example, when the SD video having 720×480 pixels is directly displayed on the display apparatus having 4000×2000 pixels, an area on which no video is displayed becomes extremely large, and the video is displayed in a small size as compared to the screen size. As the high definition display apparatus represented by the digital cinema or the like has a large screen, the video is viewed by a viewer at a place relatively remote from the screen. Therefore, the video displayed in the small size is difficult to recognize.
For this reason, there is known a method of magnifying a low resolution video to a full screen by using a technique disclosed in Japanese Patent Laid-Open No. 5-252457 in accordance with a predetermined display mode such as a size panel display or a letter box display.
According to the technique disclosed in Japanese Patent Laid-Open No. 5-252457, it is possible to magnify a signal with any resolution to a predetermined size such as a full screen size of the display. However, in a case where the video is magnified to the predetermined size, the image is blurred due to an influence of an image processing such as a pixel interpolation processing. In particular, as compared with a case where a video originally having the large number of pixels, a magnifying factor for a low resolution video having the small number of pixels becomes also large. In other words, the influence of the image quality degradation caused by the magnification processing is large in the lower resolution video.
Therefore, in a case where the low resolution or low image quality video content is magnified and displayed on the high definition display apparatus, it is necessary to execute such a contradict control that the visibility of the viewer should not be lowered and the image quality degradation caused by the magnification processing is suppressed.